Well cross-over apparatus and tools and method of operating a well installation



METHOD Sheet J. V. FREDD -OVER APPARATUS AND TOOLS AND OF OPERATING AWELL INSTALLATION S s O R c 7 9 W l 6 I 9 O 1 l m 9 r a 2 M l l p l A FZNVENTOR ohn V. Fredd ATTORNEYS Apnl 29, 1969 J. v. FREDD 3,441,084

WELL CROSS-OVER APPARATUS AND TOOLS AND METHOD OF OPERATING A WELLINSTALLATION Filed March 10, 1967 Sheet 2 of s Fig.5 INVENTOR John V.Fredd BY Wymw ililiiim/lili mb Aprll 29, 1969 .1. v. FREDD 3,441,084

WELL CROSSOVER APPARATUS AND TOOLS AND METHOD OF OPERATING A WELLINSTALLATION Filed March 10, 1967 Sheet 3 Fl .7- g B: W

2 ATTORNEYS April 29, 1969 v, FREDD 3,441,084

WELL CROSS-OVER APPARATUS AND TOOLS AND METHOD OF OPERATING A WELLINSTALLATION Filed March 10, 1967 Sheet 4 of s Fig. iz-A INVENTOR JohnV. Fredd J. V. FREDD April 29, 1969 WELL CROSS-OVER APPARATUS AND TOOLSAND METHOD OF OPERATING A WELL INSTALLATION Sheet Filed March 10, 1967 IINVENTOR John V. Fredd BY] ATTORNEYS J. v. FREDD 3,441,084 WELLCROSS-OVER APPARATUS AND TOOLS AND METHOD April 29, "1969 OF OPERATING AWELL INSTALLATION Filed March 10, 1967 Sheet R m 0 B d M w Y B F V El nh .J O 7 J a i 3 Wm F E w g F EHN ATTORNFYS April 29, 1969 J. v. FREDD3,

WELL CROSS-OVER APPARATUS AND TOOLS AND METHOD OF OPERATING WELLINSTALLATION Filed March 10, 1967 Sheet 8 of a INVENTOR John V. FreddATTORNEYS United States Patent M 3,441,084 WELL CROSS-OVER APPARATUS ANDTOOLS AND METHOD OF OPERATING A WELL INSTALLATION John V. Fredd, Dallas,Tex., assignor to Otis Engineering Corporation, Dallas, Tex., acorporation of Delaware Filed Mar. 10, 1967, Ser. No. 622,262 Int. Cl.E21b 23/00 US. Cl. 166-250 39 Claims ABSTRACT OF THE DISCLOSURE A wellapparatus having a pair of flow conductors extending in a well andhaving means for releasably securing well tools in the flow conductorsat predetermined spaced locations therein and a cross-over means forestablishing fluid communications between the flow conductors to permitcirculation of fluids down one flow conductor and up the other to treatinternal surfaces of the flow conductor, to move well tools up and downone or the other of the flow conductors to position and remove welltools from the flow conductors, or to operate well tools connected inthe flow conductors below the location of communication of the two flowstreams. A crossover device connectable between a pair of flowconductors for establishing fluid flow communication between the flowconductors and operable when the pressure in both of the flow conductorsabove the cross-over device is increased above a predetermined value. Amethod of operating a well installation having a plurality of parallelflow conductors extending into a well by establishing communicationbetween -a pair of the flow conductors below the surface to permitcirculation of fluids from the surface down one of the flow conductorsand then to the surface up the other of the flow conductors to operate,install or remove well tools in such flow conductors and to establishdesired circulation between earth formations and the surface.

This invention relates to a well apparatus for control-v ling fluid flowbetween the surface and producing earth formations penetrated by thewell, to a flow control device of the well apparatus, and to a methodfor operating a well having a pair of parallel flow conductors extendingtherein.

An object of this invention is to provide a new and improved apparatusfor producing well fluids from earth formations penetrated by a wellhaving a pair of flow conductors extending through the well and havingmeans in the well below the surface of the well for establishingcommunication between the flow conductors to permit circulation offluids down one conductor and up the other to provide for treatment ofthe flow conductors with fluids, to provide for reciprocable movement ofwell tools in the flow conductors, and to provide for operation of welltools connected in the flow conductors by well tools movable through theflow conductors.

Another object is to provide a well apparatus wherein the operation ofthe means for establishing communication between the flow conductors orcross-over device is responsive to the fluid pressures in both the flowcon ductors which are controllable at the surface of the well wherebywell operations which require high pressure con ditions in one or theother of the flow conductors may be carried on without causing operationof the cross-over device and the establishment of communication betweenthe flow conductors therethrough.

Still another object is to provide a well apparatus wherein the flowconductors below the cross-over device are provided with means in whichwell tools, such as standing valves. safety valves. plugs and the like,are re- 3,441,084 Patented Apr. 29, 1969 movably installable and whereinthe well tools may be installed in and removed from the flow conductorsby operator tools connectable to a transport train movable reciprocablyin the flow conductors by the fluids circulated therein when thecross-over device is open.

A further object is to provide a well apparatus wherein the valve meansof the cross-over device is biased to closed position by the pressure inthe well exteriorly of the flow conductors and is movable to openposition against the force of such exterior pressure by the fluidpressures in the flow conductors when they are raised above apredetermined value.

A further object is to provide a well apparatus wherein the pressure forbiasing the valve means toward closed position is that in one of theflow conductors in communicaion with a producing formation of highestpressure of the well in well installations whose flow conductors arecemented in a casingless well and where such biasing pressure is thepressure above packers of a well installation whose producing formationsare separated by packers which close the well bore between producingearth formations.

A s iil further object is to provide a well apparatus of the typedescribed whose cross-over device may be tested while in the well bycontrol and test means located at the surface and without the necessityof moving tools into the well.

An important object of the invention is to provide a new and improvedcross-over device connectable between a pair of flow conductors forestablishing communication therebetween.

Another object is to provide a crossover device having a cross-overpassage which communicates with the flow passages of the flow conductorsto which the cross-over device is connected and has valve means forclosing the cross-over passage.

Still another object is to provide a cross-over device wherein the valvemeans is biased toward its closed position by pressure from exteriorlyof the cross-over device and is movable to its open position by theforce of the pressures in both of the flow conductors connected theretowhen they are increased to a value sufiiciently high that their forceovercomes the force biasing the value means to its closed position.

'Still another object is to provide a cross-over device wherein thevalve means includes a pair of valves each biased when in their closedposition towards open position by pressure from its associated flowconductor and wherein each valve when in its closed position is biasedtoward closed position by the pressure from the other flow conductor ifthe other valve is in its open position whereby the cross-over devicepermits undesired communication between the flow conductors only if bothvalves are not functioning properly.

Still another object is to provide a cross-over device having toollocating and locking means for positioning a bridge tool therein toprevent flow through the cross-over device if it is determined that thecross-over device is not functioning properly.

A further object is to provide a cross-over device having a body and apair of nipple means extending through bores in the body, the bodyhaving a main passage and a pair of passages, each of the pair ofpassages communicating with the main passage and the flow passage of oneof the nipple means and a pair of valves for preventing communicationbetween each of the pair of passages and the main passage, wherein eachof the valves when in its closed position is biased toward its closedposition by the fluid pressure in the main passage and is biased towardits open position by the pressure in the flow conductor which iscommunicated to the passage of the pair of passages which it closes.

A still further object is to provide a cross-over device having meansfor conducting fluid pressure from one of the pairs of flow conductorsin which the nipple means are connectable to constitute sections thereofor by fluid pressure from the exterior of such flow conductors to thevalves to bias them toward their closed positions.

Still a further object is to provide a cross-over device wherein thecross-over device has means for installing a flow control device, suchas a standing valve, in one of the nipple means above the location atwhich the pressure from such one of the flow conductors is conducted inorder that the pressure in such one flow conductor, which normally hasthe highest pressure therein, at all times bias both of the valvestoward closed positions.

An important object of the invention is to provide a method of operatinga well installation having a pair of parallel flow conductors extendingin a Well by establishing communication between the pair of the flowconductors below the surface by varying at the surface the pressure inthe flow conductors to open a cross-over means to permit circulation offluids from the surface down one of the flow conductors and upward flowof fluids to the surface through the other of the flow conductors.

A still further object is to provide a method of operating a wellinstallation which includes the step of operating well tools connectedin such flow conductors by tools movable through the flow conductors bythe circulation of fluids down one flow conductor above the toolspositioned therein and up another flow conductor.

Another object is to provide a method of operating a well installationwhich includes the step of installing or removing ,well tools in suchwell flow conductors below the location of communication between a pairof the flow conductors by transport tool means, to which the well toolsare releasably connectable, by a tool transport means movablereciprocably in the flow conductors.

Still another object of the invention is to provide a method ofoperating a well installation having a crossover device for establishingcommunication between a pair of flow conductors of the well installationand which is operable to establish such communication only when thepressure in both flow conductors is above a predetermined value whichincludes the step of testing the cross-over device to ascertain whetherin its closed condition it effectively prevents communicationtherethrough between the two flow conductors by increasing the fluidpressure in a first one of the flow conductors while the flow conductorsbelow the cross-over device are closed and observing at the surfacewhether the pressure increases in the other flow conductor and thenincreases the fluid pressure in the other flow conductor while the flowconductors are closed below the cross-over device and observ ing at thesurface whether the pressure increases in the first flow conductor.

Additional objects and advantages of the invention will be readilyapparent from the reading of the following description of a deviceconstructed in accordance with the invention, and reference to theaccompanying drawings thereof, wherein:

FIGURE 1 is a schematic, vertical partly sectional view, with some partsbroken away, of a well installation embodying the invention by means ofwhich the method of the invention may be practiced and showing thecrossover means of the well apparatus in open position;

FIGURES 2 and 2-A are vertical sectional views of the cross-over device,FIGURE 2-A being a continuation of FIGURE 2, showing well toolsinstalled in the nipple means of the cross-over device, the well toolsbeing shown schematically;

FIGURES 3 and 4 are sectional views taken on lines 3--3 and 4-4,respectively, of FIGURE 2;

FIGURE 5 is a fragmentary enlarged sectional view of one of the valvesof the cross-over device;

FIGURE 6 is a sectional view taken on line 6-6 of FIGURE 2-A;

FIGURES 7, 7A and 7-B are vertical sectional views taken on line 77 ofFIGURE 8, of a modified form of the well apparatus embodying theinvention, FIGURES 7A and 7B being continuations of FIGURES 7 and 7A,respectively, and showing well tools installed in nipple means of thewell apparatus, the well tools being shown schematically;

FIGURES 8 and 9 are sectional views taken on lines 8-8 and 99,respectively, of FIGURE 7;

FIGURES 10 and 11 are sectional views taken on lines 10-10 and 1111,respectively, of FIGURE 7-A;

FIGURES 12, 12-A, 12-B and 12-C are schematic vertical partly sectionalviews of another modified form of the well apparatus embodying theinvention, FIGURES 12A, 12-B and 12-C being continuations of FIGURES 12,l2-A, and 12B, respectively;

FIGURES 13, 13-A and 13-B are vertical partly sectional views with someparts broken away, of the upper well packer of the well apparatusillustrated in FIGURES 12, l2-A and 12-B;

FIGURE 14 is an enlarged vertical sectional view taken on line 1414 ofFIGURE 17 of the cross-over device of the well apparatus illustrated inFIGURES 13, 13-A and 13-B;

FIGURE 15 is a vertical partly sectional view taken on line 15-15 ofFIGURE 14; and,

FIGURES 16, 17 and 18 are sectional views taken on lines 1616, 17-17 and1818, respectively, of FIG- URE 14.

Referring now particularly to FIGURES 1 through 6 of the drawings, thewell apparatus 20 includes a pair of flow conductors 21 and 22 whichextends into a well bore 23 through a well head 24 and are cemented inthe well bore. The lower end of the first flow conductor 21 communicateswith an upper producing earth formation A through perforations 25 in theflow conductor and the cement while the second flow conductor 22 is incommunication with a lower producing formation B through similarperforations 26 in the second flow conductor and the cement. The firstflow conductor 21 has a surface control assembly 30 connected to itsupper end by means of which 'well tools may be moved into the flowconductor or may be removed therefrom and by means of which fluids underpressure may flow from the flow conductor or be introduced into the flowconductor at the surface. The surface control assembly may include abottom valve 31 of large orifice, an elongate tube or manifold 32, a topvalve 33 for closing the upper end of the tube, and a flow conduit 34having a suitable flow control device connected therein, such as apressure regulator valve 36 and a shut off valve 35. The flow conduitopens to the manifold below the top valve. The control assembly may alsoinclude a pressure gauge 37 connected to the flow conduit between theshut off valve and the manifold 32 and indicates the pressure in theflow conduit, and therefore, in the first conductor 21, when the bottomvalve 31 is closed and the top valve 33 is open.

It will be apparent that when the top valve 33 is closed and the bottomvalve 31 is open, fluids may flow from the flow conductor through theflow conduit when the shut off valve 35 is opened and that the regulatorvalve 36 may be set to permit flow of fluids from the flow conductoronly as long as the pressure in the first flow conductor at the surfaceis above a predetermined value. Conversely, fluids under pressure may beintroduced into the flow conductor to maintain the pressure therein at apredetermined value by connecting the flow conduit to a suitable sourceof fluid under pressure, such as a pump, and setting the pressureregulator valve 36 to permit flow into the first flow conductor onlywhen the pressure therein falls below a predetermined value. If it isdesired to move a well tool into the first flow conductor whilemaintaining a predetermined pressure within the first flow conductor,the valves 31 and 35 are closed, the valve 33 is opened and such welltool is inserted into the manifold through the valve 33. The valve 33 isthen closed and the valve 31 is opened to permit downward movement ofthe well tool into the first flow conductor. If such tool is to be moveddownwardly by fluid pressure introduced into the flow conductor, fluidunder regulated pressure may then be introduced into the manifold 32above such tool or assembly through the flow conduit 3-4. If such toolis to be moved downwardly by a wireline, a suitable stufling box issecured to the manifold above the valve 33 to seal about the line whilethe tool is being moved in the flow conductor by means of such line.

The second flow conductor has a similar control assembly connectedthereto which includes a bottom valve 41, a manifold 42, a top valve 43and a flow conduit 44 in which are connected a shut off valve 45 and apressure regulator valve 46. A pressure gauge 47 is connected to theflow conduit between the manifold and the shut off valve.

The flow conductors 21 and 22 may be the usual strings of tubing whosesections are connectable by the usual collars C. A cross-over assemblyfor selectively permitting circulation of fluids down one flow conductorto a location above the upper producing fo'rmation, over into the otherflow conductor, and then upwardly through the other flow conductor isconnected to the flow conductors at a location above the uppermostproducing earth formation A. The cross-over assembly includes a nippleassembly 61 which is connected in the first flow conductor andconstitutes a section thereof, a similar nipple assembly 62 which isconnected in the second flow conductor 22 and constitutes a sectionthereof, and a body or head 63 in which are mounted valves 64 and 65 forclosing ports '66 and 67, respectively, of the head. The port 66 opensto a passage 68 of the head which is in communication with the ports 69of the top nipple 70 of the nipple assembly 61 and to a main passage 71of the head to which the other port 67 also opens. The port 67 alsoopens to a passage 74 of the head which is in communication with theports 75 of the top nipple 76 of the nipple assembly 62. It will beapparent that when the valves 64 and 65 are in their open positionsfluid may circulate down one flow conductor, for example, the flowconductor 21 through the nipple ports 69, the head passage 68, the lowermain head passage 71, the head port 67, the head passage 74, and thenipple ports 75 into the other flow conductor 22. These passages andports thus constituting a cross-over passage P between the two flowconductors which is closable by the valves 64 and 65.

The top nipple 70 of the nipple assembly 61 of the first flow conductorextends through a vertical bore or passage 81 of the head whichintersects the passages 68 and 71 of the head. A pair of O-rings 82 and83 disposed in annular recesses which open to the aperture 82 above andbelow the passage 67 seal between the top nipple 70 and the head andbelow the passage 68 and the ports 69 of the top landing nipple. Themiddle O-ring 83 and a bottom O-ring 84 also disposed in an internalannular recess of the head seal between the head and the landing nipple70 above and below the passage 71.

The top landing nipple 76 of the nipple assembly 62 similarly extendsthrough a vertical aperture 86 of the head which intersects the passages74 and 71. O-rings 87 and 88 disposed in annular recesses of the headseal between the head and the top nipple 76 above and below the passage74 of the head and the ports 75 of the top nipple. O-ring 88 and abottom O-ring 89, also disposed in an internal annular recess of thehead, seal between the top nipple and the head above and below thepassage 71.

The valve 64 has an annular resilient seal 91 disposed in an annulargroove or recess 92 thereof which is engage able with a seat ring 93secured as by solder and the like to the valve body and which extendsabout the port 66. The seal is secured to the valve by a split retainerring 94 whose internal lower flange is received in an annular recess ofthe valve, The valve has a stem 98 which extends slidably through afitting 100 whose upper portion extends into the lower end of a bore 101which opens to the passage 71. The fitting is held against downwardmovement in the bore 101 by a retainer sleeve 102 threaded in the lowerend of the bore whose annular top end surface engages the downwardlyfacing annular stop shoulder 104 of the top external annular flange 105'of the fitting An O-ring 106 disposed in an internal annular recess ofthe fitting seals between the fitting and the valve stem and a similarO-ring 107 disposed in an external annular recess disposed in anexternal annular recess of the fitting seals between the fitting and thebody.

The valve 64 is biased towards its upper closed posi= tion by a spring110 Whose upper portion is received in the downwardly opening bore 111of the valve stem and whose top end bears against the downwardly facingshoulder or surface 112 defining the upper end of the bore. The bottomend of the spring engages the upwardly facing annular shoulder 113 ofthe fitting. The valve 64 is also biased towards its closed position byfluid pressure in the second flow conductor below the bottom landingnipple 114 of its nipple assembly 61 which is communicated to the lowerend of the fitting by means of the vertical passage 115 of a block 115aof the cross-over assembly in whose upper threaded portion 116 isthreaded the lower end of the bottom landing nipple 114 and in whoselower threaded portion 117 is threaded the upper end of the section 118of the second flow conductor, a passage 120 of the block which opens tothe passage 115 and to the lower end of a conduit 121 threaded, as at134, in the vertical portion of the passage 120, the passage of theconduit, and a coupling 122 which conmeets the upper end of the conduitto the lower end of the fitting.

The valve 65 and the means by which it is mounted for movement betweenits open and closed positions being similar to the valve 64 and itsmeans, the valve and its associated means have been provided with thesame reference numerals, to which the subscript a has been added, as thecorresponding elements of the valve 64 and its associated means. Theconduit 121a whose upper end is connected to the bottom end of thefitting 100a by the coupling 122a has its lower end threaded in theupper vertical portion of the passage 120a of the block 115:: which alsoopens to the passage 115 below the bottom landing nipple 114 so that thevalve 65 is also biased. upwardly by the pressure in the second flowconductor below its bottom landing nipple as well as by its spring 110a.

The bottom landing nipple of the nipple assembly 61 is threaded in theupper portion of the vertical passage 123 of the block 115a, in whoselower portion is threaded a lower section 124 of the first flowconductor, and has an internal annular flange 126 which provides an upwardly facing annular stop shoulder 127 and an interal annular lockrecess 128 adjacent its upper end so that any suitable well tool, suchas a standing valve 130, may be releasably secured in the first flowconductor by means of a suitable lock means 132, such as the Otis Type NLock Mandrel illustrated on page 3816' of the Composite Catalogue of OilField Equipment and Services, 1966-67 Edition, which has a no-go ring133 engageable with the stop shoulder 127 to limit its downward movement through the landing nipple and with dogs 134 which are movable intothe lock recess 128 to releasably lock the lock mandrel against upwardmovement in the bottom landing nipple. The lock mandrel also has a sealmeans 135 which engages the seal surface of the bottom nipple to sealbetween the mandrel and the nipple so that all flow of fluids throughthe first flow conductor must take place through the standing valveconnected as at 136 to the bottom end of the lock mandrel. The standingvalve has a ball 137 biased towards its bottom closed position by aspring 138 wherein it prevents downward flow of fluids through thevalve. The operation of the lock. mandrel and the standing valve arewell known and. will not be described in greater detail.

The top nipple 70 is connected to the bottom nipple by a coupling orspacer 139. The top nipple has a lower portion of decreased internaldiameter which provides an upwardly facing annular stop shoulder 140 andan internal seal surface 141. An annular internal lock recess 142 isalso provided below the stop shoulder so that a lock means 143, such asthe Type E Otis Mandrel illus trated and described on page 3817 of theComposite Catalogue of Oil Field Equipment and Services 1966-67 Edition,may be releasably locked and located in the top nipple 70 to holdanother well tool 144, such as an Otis Type F Tubing Safety Valveillustrated and described on page 3836 of the 1966-67 Edition of theComposite Catalogue of Oil Field Equipment and Services, in the firstflow conductor. The safety valve prevents upward flow of fluidstherethrough when the pressure differential across the safety valveexceeds a predetermined value, as for example, in the event of failureor damage to the surface well equipment which would otherwise result inunrestricted fluid flow through the first flow conductor. The lockmandrel 143 has a no-go ring 145 which is engageable with the stopshoulder 140 of the top landing nipple to limit downward movement of thelock mandrel through the top nipple, dogs 146 which are receivable inthe lock recess 142 for releasably locking the lock mandrel againstupward movement in the top nipple and seal means 147 engageable with theseal surface 141 so that all fluid flow takes place through the safetyvalve and the lock mandrel.

The top nipple also has an upper lock recess 148 near its upper end anda seal surface 149 below its upper lock recess whose function will bedescribed below.

The bottom landing nipple 114 of the nipple assembly 62 may be identicalto the bottom landing nipple 125 and have a bottom internal flange 151which provides an upwardly facing annular stop shoulder 152, a sealsurface 153 and a lock recess 154 so that a lock mandrel 155 and astanding valve 156 carried thereby, which may be identical to the lockmandrel 132 and the standing valve 130 may be releasably locked in thesecond flow conductor in the position illustrated in FIGURE 2A. Thebottom nipple 114 is connected to the top nipple 76 by a flow coupling157. The top nipple 76 may be identical in structure to the nipple 70and having a bottom seal surface 158, a lower internal annular lockrecess 159, an annular stop shoulder 160, an upper seal surface 161 andan upper lock recess 162. It will be apparent that a safety valveidentical to the safety valve 144 may be installed in the same mannerand by a lock mandrel identical to the lock mandrel 143 to controlupward flow of fluids through the second flow conductor.

The well apparatus is installed in the well bore by connecting thecross-over assembly or device 60 to the two flow conductors, asillustrated in FIGURES 1 and 2, with the two nipple assemblies 61 and 62thereof con nected in and constituting sections of the first and secondflow conductors 21 and 22, respectively. The flow conductors are loweredby usual means and methods into the well bore 23 to a desired positiontherein wherein the cross-over assembly is positioned above the upperpro= ducing formation A and each flow conductor extends downwardly pastthe producing earth formation whose fluids it is to conduct to thesurface. The flow conductors and the cross-over device are then cementedin place in the well bore, as illustrated in FIGURE 1, by anyconventional method, as by pumping a cement slurry through one or bothof the flow conductors into the well bore until the well bore about theflow conductors is filled with cement slurry. The flow conductors 21 and22 are, of course, cleared of any cement slurry, as by pumping a fluidsuch as water into the flow conductors at the surface, after a charge ofcement slurry of sufficiently great volume to fill the well bore to thesurface has been pumped into the flow conductors to locations below theproducing formations A and B, respectively. The cement, of course,closes or plugs the flow conductors below the producing formations.

After the cement has set in the well bore, suitable directionalperforating tools are moved through the two flow conductors to thelocations of the producing earth formation to form the perforations 25and 26 through the flow conductors and the cement so that well fluidsfrom the formation A may then flow into the flow conductor 21 and fromthe producing formation B into the second flow conductor 22.

The standing valves are then installed in the bottom nipples of the twonipple assemblies and locked therein by means of their lock mandrels.The lock mandrels may be lowered into position and locked in place by aset of suitable wire line operated tools, which may include a suitablerunning tool to which the lock mandrels are releasably secured, such asthe Otis Type H Running Tool illustrated and described on page 3839 ofthe Composite Catalogue of Oil Field Equipment and Services, 1966-67edition. Such tools are inserted into and removed from the flowconductors by means of suitable surface control assemblies connected tothe upper ends of the two flow conductors in the usual well knownmanner. For example, if a standing valve is to be lowered into the firstflow conductor by means of a wire line and a string of wire line toolswhich includes jars, the string of wire line tools and the lock mandrel132 and standing valve 130 connected thereto are lowered into themanifold 32 while the lower valve is closed and the upper valve 33 isopen. A suitable stufling box secured to the upper end of the manifoldabove the upper valve 33 closes the upper end of the manifold about thewire line during the movement of the tools through the first flowconductor. The valve 31 is opened and the well tools are lowered throughthe first flow conductor until the downward movement of the lock mandrel132 is arrested due to the engagement of its nogo ring 133 with the stopshoulder 127 of the bottom landing nipple. Downward jars are thenimparted by means of the wire line tools and the wire line to the lockmandrel to cause its locking dogs 134 to move into the lock recess 128and also to release the running tool from the lock mandrel. The stringof wire line tools is then re moved from the well and lock mandrel leftreleasably locked in the bottom nipple. Subsequently and in similarmanner another well tool, such as the safety valve 144, may be installedin the top nipple of the nipple assembly 61 by means of a lock mandrel143. The standing valve 156 and a safety valve identical to the safetyvalve 144 may be similarly installed in the nipple assembly 62 throughuse of wire line tools or a tool string movable through the flowconductor 22 by circulation through the crossover assembly. The standingvalves prevent imposition of excessive pressures on the producing earthformations during subsequent operations of the well apparatus as well asthe movement of fluids which may be introduced into the flow conductorsat the surface into the producing formations.

The flow conduits 34 and 44 may then be connected to reservoirs ordelivery lines to which the fluids produced from the formations A and B,respectively, are to be transported. The pressure regulator valves 36and 46 are preferably set to maintain predetermined pressures in the twoflow conductors and thus control the rate of production of well fluidsand the shut off valves 35 and 45 are then opened. If the rate of flowthrough any flow conductor in which a safety valve is installed exceedsa predetermined value, such safety valve will close.

During normal well fluid producing operations of the well apparatus, thevalves 64 and 65 are held in their closed positions by the forcesexerted thereon by their biasing springs and by the pressure in thesecond flow conductor below its standing valve 156. The flow passages120 and 120a of the block a open to the passage 115 of the block whichis in communication with the flow conductor in which the highestpressure is maintained in order that both valves be in their closedpositions during normal operation of the well apparatus and that atleast one of the valves be biased toward closed position by a forcesubstantially greater than that exerted by its biasing spring; In theillustrated apparatus, it is assumed that the pressure in the secondflow conductor is higher than the pressure in the first flow conductor,and therefore, the passages 120 and 120a open to the passage 115 of theblock which constitutes a section of the flow passage of the second flowconductor. If the pressure in the first flow conductor was to bemaintained at a higher value than in the second flow conductor, thepassages 120 and 120a would open to the passage 123 of the block insteadof to the passage 115.

The valves are also biased toward their closed positions by any fluidpressure trapped in the main passage 71 of the head since the areas ofthe valves within the lines of sealing engagement of the seals 90 and90a with their seat rings are greater than the areas of the valve stems98 and 98a within the lines of sealing engagement of the O-rings 106 and106a therewith.

It will be apparent that if the pressure in the first flo conductor atthe cross-over assembly of the illustrated apparatus were greater thanthe fluid pressure in the second flow conductor at the location of thepassage 115, as perhaps may sometimes be required during certainoperations of the well apparatus, the forces of this fluid pres-* sureexerted on the upwardly facing surfaces of the valve 64 through the topnipple port 69, the passage 68 and the port 66 could exert a force somuch greater than the combined force of the spring 110, the force of theliquid pressure from the second flow conductor exerted on the downwardlyfacing surfaces of the stem 98 and of any fluid pressure trapped in themain passage 71 of the head, that the valve 64 could move to its openposition. This would not result in the establishment of communicationbetween the two flow conductors since even if the valve 64 were open andthe fluid pressure from the first flow conductor were communicated tothe main passage 71, the force exerted on the valve 65, as long as thevalve 65 is closed, by the pressure in the main passage would bias ittoward its closed position. It is preferable, however, that at least oneof the valves have a pressure differential exerted thereacross duringnormal production operation of the well apparatus which increases theforce with which such valve is biased toward closed position, it beingapparent that the valve 65 during normal production operation of thewell is biased to its closed position mainly by the force of the spring110a since the pressure within the passage 74 of the cross-over head issubstantially equal to the pressure in the passage 115, and the pressuretrapped in the main chamber may not be of high value, since some leakageof well fluids could possibly take place past the valve 65 from thepassage 71 to the port 67 if the spring 110a exerted a relatively smallforce on the valve 65 during prolonged periods of such productionoperation.

It is sometimes desired to circulate fluids down one of the flowconductors through the cross-over passage and upwardly in the other flowconductor, as for example, in order to treat the internal surfaces ofthe two flow conductors with a corrosion inhibiting liquid or todissolve and remove deposits or paraflin or other such substances whichmay have accumulated on the internal surfaces on one or both of the flowconductors. Such deposits normally accumulate at higher locations in theflow conductors above the cross-over assembly where the temperatures arelower than in the lower portions of the well. In this case both flowconduits 34 and 44 are connected to a suitable source of the treatingliquid by means of a pump and their shut otf and regulator valves areopened. The pressures in the two flow conductors, since they are nowboth connected to a single source of pressure, now

be raised to equal values at the location of the crossover assembly. Asthe pressure in the flow conductors rises as such pump operates, thestanding valves of the two flow conductors close and prevent downwardflow of fluids from the flow conductors into the producing formations Aand B. The valves 64 and 65 are biased upwardly with substantially equalforces since their springs are of equal strength and their stems areexposed to the same formation B pressure. When the pressure in the twoflow conductors is increased to a value sufficiently great that itsforce exerted on the valves 64 and 65 exceeds the upward force exertedon these valves by their springs and by fluid pressure within the secondflow conductor 22 below the standing valve 156, the valves 64 and 65will move simultaneously to their open position. The seals and 90a. willnot be subjected to great pressure differentials during this openingmovement since the pressures in the two flow conductors are equal, itbeing ap parent that if such opening of the valves took place at thetime great pressure diflerentials existed thereacross, the seals couldbe damaged by the forces exerted thereon.

If it is then desired that the treating fluid circulate down one flowconductor, for example, the flow conductor 21 and up the other flowconductor 22, the pressure regu lator valve 46 of the flow conduit 44 isset to maintain a back pressure in the second flow conductor 22sufficiently great that the valves 64 and 65 will be held in their loweropen positions. The conduit 44 is then disconnected from such commonsource of fluid under pressure and connected to a disposal line to whichthe treating liquids after their circulation through the flow conductorsmust be delivered. The treating liquid is then pumped through theconduit 34 into the manifold 32 and thus into the top end of the firstflow conductor, flows downwardly through the first flow conductor to thecross-over assembly, then through the cross-over passage of the assemblyinto the second flow conductor, upwardly through the second flowconductor and to the flow conduit 44. At this time, if the pressure inthe flow conduit 34 is raised over the value required to open the valve64, for example, if the pressure is raised psi. over such valve, thepressure in the flow conduit 44 may be decreased equally since thepressure at the cross-over device will remain substantially equal tothat before the pressure was increased in the flow conduit and wasdecreased in the conduit 44. When the circulation of such treatingliquid is completed, the shut 01f valves 35 and 45 are closed, the flowconduits 34 and 44 are again connected to the storage reservoirs or flowlines to which the well fluids must be delivered, and, when the shut offvalves 35 and 45 are again opened after the regulator valves have beenset to maintain the pressure in the two flow conductors at desiredvalues, as the pressures in the flow conductors decrease due to the flowof fluids therefrom through their flow conduits, the force of thesprings and of the pressure in the second flow conductor below thecross-over assembly causes the valves 64 and 65 again to move to theirupper closed positions. As the valves move to their closed positions,any relatively high pressure trapped in the main passage will exert aforce on the valves tending to hold them in their closed positions dueto the fact that the areas of the valves exposed thereto within thelines of sealing engagement of the seals of the valves are greater thanthe areas of their stems exposed thereto Within the lines of sealingengagement of the O-rings 106 and 106a therewith. Each flow conductorthen produces fluids from its respective earth formation.

It will be apparent, that, if desired, the flow conduits 34 and 44 mayboth be connected to a disposal line for such treating liquids after thecirculation thereof is completed for a period of time sufliciently longto cause all treating fluids in the flow conductors and the flowconduits to be flushed out by the well fluids produced by the formationsprior to the connection of the flow conduits to the reservoirs or flowlines to which such well fluids are to be delivered.

Well tools removably installed in one or the other f the flowconductors, such as the safety valve 144 installed in the top nipple 70of the first flow conductor 21 may be removed therefrom by means of apump down train of tools 200, which may be similar to the Otis Pump-.Down Train of Tools illustrated on page 3780 of the Composite Catalogueof Oil Field Equipment and Services, 1966-67 edition, and includelocomotives 201 and 202, jars, not shown, and the like, as Well as apulling tool 203 such as the Otis Type R Pulling Tool illustrated anddescribed on page 3839 of the Composite Catalogue of Oil Field Equipmentand Services, 196667 edition. Such tools are preferably connected to oneanother by suitable couplings which permit a limited pivotal movement ofeach tool of the train at the location of its connections to the othertools of the train. The locomotives 201 and 202 sealingly engage theinternal surfaces of the flow conductor to close its passage and arespaced far enough apart to bridge any internal recesses of the flconductor, such as coupling collar recesses. The train f tools with thepulling tool at its bottom end is then placed into the manifold 32 afterthe valves 31 and 35 have been closed and the top locomotive 101 ispositioned below the location of communication of the flow conduit 34with the manifold 32. The valve 33 is then closed and the valves and theflow conduits 34 and 44 are connected to a common suitable source offluid under pressure and the pressure in the flow conductors is raisedto a value sufliciently high to cause the standing valves of the flowconductors to close and the valves 64 and 65 t open. The pressureregulator 46 is then set to permit flow from the first flow conductorwhen the pressure therein exceeds a predetermined value which, however,is sufficiently high to keep the valves 64 and 65 in their openposition. The pressure of the fluid introduced into the first fiowconductor is then raised to a sufiiciently high pressure to move thetrain of tools downwardly and cause the fluids in the first flowconductor below the bottom locomotive to flow downwardly therein,through the crossover passage of the cross-over assembly and thenupwardly through the second flow conductor to its flow conduit 44.

The bottom locomotive 102 is spaced from the pulling tool 203 a distancesutficiently great that when the train of tools has moved downwardly tothe position wherein the pulling tool has moved into operativeengagement with the upper end portion of the lock mandrel 143, thebottom locomotive is positioned above the ports 69 f the top nipple 70.Once the pulling tool has moved into operative and connected engagementwith the lock mandrel, the direction of flow of fluids through the flowconductors is reversed, the flow conduit 44 being connected to a sourceof fluid under pressure and the flow conduit 34 being opened through itsvalve 55 and pressure regulator valve 56 which is now set to maintainthe pressure in the first flow conductor above that necessary tomaintain the valves 64 and 65 in their open positions. The fluid thenflows down through the second flow conductor and the cross-over passageto the first flow conductor below the bottom locomotive. The train oftools is now moved upwardly in the second flow conductor and since thepulling tool is now secured to the lock mandrel, the lock mandrel andthe safety valve now move upwardly with the train and into the manifold32. The train of tools may then be removed after the valve 31 is closedand the valve 33 is opened.

Another well tool may then be installed in the top nipple 70, such as anew or repaired safety valve 144, by connecting at the bottom end of thepump down train, instead of the pulling tool, a running tool, such asthe Type T Otis Running Tool illustrated and described on page 3892 ofthe 1966-67 Catalogue of Oil Field Equipment and Services, to which thelock mandrel 143 Of Cir the safety valve is secured with its dogs heldin retracted position. The train of tools is then inserted into thefirst flow conductor and pumped down until the lock mandrel moves intothe top nipple 70 and is latched therein by its dogs which are thenmoved to their expanded positions in the lock recess 148. The runningtool is released from the lock mandrel by a downward force or jarsimparted thereto by the train of tools as the pressure in the first flowconductor is increased at the surface by operation of the surfacecontrols. The direction of circulation of fluids in the flow conductorsis then reversed and the train of tools is removed upwardly through andfrom the first flow conductor.

It will be apparent that the well tools may similarly be installed inand removed from the landing nipples of the second flow conductor bysimilar running and pulling tools connected to such a pump down train.

It is apparent that it is necessary'to remove well tools from eachlanding nipple before the well tool in the next lower landing nipple maybe removed.

It will also be apparent that while each of the nipple assemblies 61 and62 has been illustrated as having only two nipples in which lockmandrels may be releasably installed that additional such nipples may beconnected between the top and bottom nipple in spaced relation to oneanother and to the top and bottom nipples by suitable couplings, such asthe couplings 139 and 157. The lengths of the conduits 121 and 121awould, of course, be increased accordingly.

It will also be seen that, if desired, even the standing valves may beinstalled in or removed from the bottom nipples by the pump down trainof tools, the high pressure in the flow conductors below the lowermostlocomotive 102 of the pump down train Will, however, be imposed on theproducing earth formations as the standing valves are moved from thelanding nipples.

While the surface control assemblies 30 and 40 have been shown connectedto the two flow conductors at the surface of the well, it will beapparent that in some installations, as for example, in subsea wells,the flow conductors may extend a relatively long distance from the wellhead to the shore of the body of water and such control assemblies arethen connected at such locations remote from the well itself and theflow conductors may have bends or arcuate portions therein. The flexibleconnection of the various tools of the pump down train, however, permitssuch pump down train of tools together with the well tool which is beinginstalled or removed from the flow conductor to move through sucharcuate portions of the flow conductors. In this case the lock mandrelsmay be formed of several sections flexibly connected to one another andthe well tool carried by such lock mandrel Will also preferably beflexibly connected to the lock mandrel.

It will also be apparent that while particular well tools have beenillustrated and described for installation in particular nipples inconnection with the operation of the well installation 20, other welltools, such as chokes, plugs, and the like, may be moved and operatedthrough the flow conductors of the well installation 20 and may beprovided with other lock means adapted to cooperate with nipples otherthan those illustrated and described in con nection with the wellinstallation 20.

It is important in well installations having a plurality of flowconductors which produce fluids from different producing formations thatno commingling of the well fluids produced by different formations occurduring their production by flow thereof from one such flow conductor toanother, as through the cross-over assembly 60 of the well apparatus 20when its valves are in their closed positions, in order that the ratesof production from the different formations can be measured andcontrolled. It is, therefore, necessary that the well apparatus afterits installation and after each opening and closing of the cross-overpassage, and at periodic intervals as may be 13 required by variousgovernmental bodies which regulate the production of well fluids, suchas gas and oil, be capable of testing the cross-over assembly todetermine if the cross-over passage is effectively closed.

The operative condition of the cross-over assembly 60 may be easily andpositively tested Without introducing any well tools into the wellmerely by closing the shut off valves of the flow conductors if the shutin pressure of the formation B in the second flow conductor isconsiderably greater than the shut in pressure of the formation A in thefirst flow conductor When the shut off valves are closed the springs ofthe standing valves move the balls thereof to their closed positions asthe shut in values of the formation pressure are reached in the flowconductors. If the valves 65 and 64 are properly closing the gcross-over passage the pressure gauge 37 will not indicate a rise in thepressure in the first flow conductor above the normal shut in pressureof the first flow conductor thus indicating that no fluid fiow has takenplace between the two flow conductors through the cross-over passage P.

Alternatively, after the shut-off valve 35 is closed, the conduit 44 maybe connected to a source of test fluid of higher pressure than thenormal shut in value of the formation pressure B in the second flowconductor 22 at the surface. The standing valve 156 will close and thevalve 65 will open as the pressure in the second flow conductor is thusincreased. It the valve 64 is now not properly closing the cross-overpassage, the pressure gauge 37 will indicate a rise in the pressure inthe first flow conductor at the surface above the normal shut in valueof the formation A. If desired, the cross-over assembly may be furthertested by closing the shut-in valve 45, and connecting the flow conduit34 to a source of pressure higher than the normal shut-in pressure ofthe producing forma tions in the flow conductors at the surface of thewell. As the pressure in the first flow conductor increases, thestanding valve 132 Will close and the valve 64 is moved to its openposition. If the valve 65 is now not properly closing the cross-overpassage, the pressure gauge 47 will indicate a rise in the pressure inthe second fiow conduc tor at the surface above that of the shut-inpressure of the producing formation B thus indicating that the valve 65is not functioning properly.

It will thus be apparent that it is possible to test the cross-overassembly to determine whether it is in proper functioning condition andthat it is also possible to test. each valve separately.

If the valve 65 is not functioning properly, the higher pressure in thesecond flow conductor which is then communicated to the main passage 71of the head will cause a pressure differential to exist across the valve64 and its stem biasing the valve 64 to its closed position due to thedifference in the areas within the seal 90 and the O-ring 106 and sincethe pressure in the first flow conductor is lower than in the secondflow conductor, Any malfunctioning of the valve 65 will not result inany fluid flow between the two flow conductors through the cross-overpassage P if the valve 64 is operating properly. If the valve 64,however, is not functioning properly and if the pressure within thesecond flow conductor is considerably greater than in the flow conductor21, the valve 65 could be moved to its open position if the pressure inthe main passage 71 decreased considerably due to flow from the mainpassage into the port 66 and the force of the pressure in the secondflow conductor exerted on the upwardly facing area of the valve 65through the port 67 became sufiiciently great to move the valve 65downwardly against the upward force exerted by the spring 110a, by thepressure acting on the stem 98a below the O-ring 106a and by thepressure in the main passage acting on the valve 65. The spring 110a ispreferably of such strength that under predictable pressure conditionsin the well apparatus it prevents such undesired opening of the valve65.

If one or the other of the valves is not functioning properly because ofpressure of extraneous matter, such as scale, sand and the like, on thevalve or its seat ring, the circulation through the cross-over passagemay be reversed several times while both valves are held open to causethe fluids flowing therepast to dislodge such matter. After suchflushing circulation, the valves will, of course, be tested again.

If it is found that the cross-over assembly is not functioning properly,a suitable bridge tool may be installed in the top nipple of either flowconductor to close the ports 75 or 68 to prevent flow through the ports75 or 68 as desired as will be explained in connection with a preferredform of the well apparatus 2% embodying the inventio illustrated inFIGURES 7 through 11.

Upon the termination of the testing of the cross-over device or upon thetermination of circulation of fluids through the two flow conductors bymeans of the crossover device, the pressure in one or both of the flowconductors is decreased by operation of the surface controls thereof andthe valve or valves which have been open will move upwardly to closedpositions while the pressure in one or both of the flow conductors ishigher than that normally obtaining therein during normal production offloW of well fluids by the well apparatus. As a result, the fluidpressure trapped in the main passage 71 upon the closing of the valve orvalves is higher than the normal fluid pressure in either one of the twoflow conductors. This trapped fluid pressure then exerts an additionalforce biasing the two valves toward their closed positions. The fluidstrapped in the main passage are not completely incompressible liquidssince the fluids in the flow conductors normally are a mixture of gasesand liquids. In any event, any movement of the valves resulting inpartial opening of the ports 66 and 67 is very small and does notdecrease the volume of the chamber to any appreciable degree so that theports are opened slightly as either valve is initially moved from itsclosed toward its open position and any fluids trapped in the mainpassage which must be displaced from the main passage as the valve movesdownwardly thereinto may escape from the main passage through suchpartly opened port.

It will be apparent that since the pressure in both of the flowconductors must be increased above the value predetermined by the forcesexerted by the springs of the two valves thereon, by the fluid pressurein one of the flow conductors and by any fluid pressure trapped in themain passage, various operations may be performed by means of the wellapparatus 20, during which it is not desired to establish fluid flowcommunication between the two flow conductors through the cross-overdevice, which, however, require the raising of the pressure in one orthe other of the two flow conductors to a value above that which causesits associated valves 64 and 65 to move to its open position. Forexample, it may be desired to treat the formation A with treatingliquids under relatively high pressure, as for example, to stimulate theproduction of well fluids from the formation A by the introductionthereinto of liquids which increase the permeability of the formation tosuch well fluids, as by fracturing the formation in the vicinity of thewell bore or by removing from the formation connate water or waterintroduced into the formation during the drilling of the well bore.

In this case, any well tools located in the first fiow conductor 21,such as the safety valve 144 and the standing valve 130, are removedtherefrom either by wireline tools or by pump down trains of tools asdescribed hereinabove. The flow conduit 34 is then connected to a sourceof such treating liquids which are then introduced into the upper end ofthe first flow conductor through the surface control assembly 30 andwill flow downwardly through the first flow conductor and through theperfora tions 25 into the producing formation A. As the pressure in thefirst flow conductor is thus increased, the valve 64 will open but thevalve 65 will remain closed since the now high pressure in the mainpassage 71 will actually exert a greater upward force on the valve 65biasing it toward its closed position.

Similarly, if it is desired to test any of the well tools which areinstalled in the flow conductors, as for example, the standing valve 156of the second flow conductor, the flow conduit 44 is connected to asource of fluid of pressure higher than the shut-in pressure of thesecond flow conductor, and after the pressure in the second flow conductor has been raised to such higher pressure, the shut off valves 35and 45 are closed. If the standing valve 156, which is moved to itsclosed position as the pressure thereabove was increased and the valve64 are functioning properly, the pressure gauge 47 will show no decreasein pressure in the second flow conductor and the pressure gauge 37 willshow no increase in the pressure in the first flow conductor above itsshut-in pressure. If the pressure gauge 47 shows a decrease in thepressure in the second flow conductor and the pressure gauge shows nosuch increase in the pressure in the first flow conductor, it will beapparent that the standing valve 156 is permitting downward flowtherethrough and is defective.

It will now be apparent that the cross-over device or assembly 60provides for a great flexibility of operation of the well apparatus dueto the provision of a valve means for closing its cross-over passage Pwhich includes two separate valves, each of which is capable ofindependently closing the cross-over passage P to flow of fluids betweenthe two flow conductors, for a great reliability of operation, and for along operational life since both valves and the elements associated witheach valve, such as the spring, or the seat rings against which thevalves seat must fail, before actual fluid flow can take place betweenthe two flow conductors through the crossover device.

It will further be seen that the cross-over device includes nippleassemblies which are connectable in the flow conductors to constitutesections thereof and which have means for locating and locking welltools therein to control flow of fluids through the flow conductors.

It will also be seen that the cross-over device has means utilizing thefluid pressure in one of the flow conductors for biasing the valves ofthe cross-over device toward their closed positions.

The well apparatus 20b embodying the invention illustrated in FIGURE 7,is similar to the well apparatus 20, and, accordingly, its elements havebeen provided with the same reference characters, to which the subscriptb has been added, as the corresponding elements of the well apparatus20. The well apparatus 20b differs from the well apparatus 20 in havingthe longitudinal axes of the valves 64b and 65b located in a verticalplane perpendicular to the vertical plane in which lie the longitudinalaxes of the nipple assemblies 61b and 62b instead of in a single commonvertical plane as in the case of the well apparatus 20 in order tominimize the external diametric dimensions of the cross-over device 60b.In addition, the nipple assembly 61b includes only a top landing nipple70b and a flow coupling or conduit 13% and the first flow conductorbelow the block 115ab has a plurality of spaced landing nipples 251 and252 connected therein by means of which well tools such as a standingvalve 253 and a safety valve 254 may be releasably secured in the firstflow conductor below the cross-over device 60b in such landing nipples,

The landing nipples of the first fiow conductor may be of the typedescribed and illustrated in the patent to J. V. Fredd, No. 2,798,559,issued July 9, 1957, each having selector key grooves 255 and a lockgroove 256 in which are receivable selector keys 257 and lock means ordogs 258, respectively, of the locator and lock tools or lock mandrels259 and 2600 to which the standing valve and the safety valve areconnected. The lock. mandrels may be of the type described andillustrated in the patent to J. V. Fredd and also on page 3836 of theComposite 16 Catalogue of Oil Field Equipment and Services, 1966-67Edition, wherein is also illustrated and described a safety valve whichmay be used as the safety valve 254. The selector key grooves of eachlanding nipple may be of different dimensions or differently spaced thanthe grooves of the other nipples connected in the flow conductors andthe lock mandrels of the different well tools are provided with selectorkeys of different configurations so that each well tool may be locatedand locked in a preselected landing nipple of the first flow conductorbelow the cross-over device assembly by means of i.s lock mandrel. Itwill be apparent that the lock mandrel of the standing valve 253 may belocated and locked in the bottom landing nipple 251 and the lock mandrelof the safety valve 254 may be located and locked in a landing nipple252b by means of wireline or pump down tools in the same mannerdescribed above in connection with the well apparatus 20.

It will be apparent, of course, that the bottom locamotive of a pumpdown train of tools connected to the running or pulling tools, by meansof which such lock mandrels are installed in or removed from the landingnipples 251 and 252, must be spaced above such running and pulling toolsa distance sufficiently great that when such running or pulling tool isin engagement with the upper portion of the lock mandrel when such lockmandrel is locked in its landing nipple, the bottom locomotive of suchtool train is above the ports 69b. The nipple assembly 62b is identicalto the nipple assembly 62 illustrated in FIGURES 1 and 2 and may havewell tools in stalled therein in the same manner as described above inconnection with the well apparatus 20. A standing valve is shown lockedin place in the bottom landing nipple of the nipple assembly 62b by alock mandrel 155b. The valves are biased upwardly by pressure in thenipple assembly 62b below the standing valve, the passages a and 12% ofthe block 115ab opening to the assembly 62b.

It will also be apparent that the cross-over device 60b may be operatedin the same manner as the cross-over device 60 to permit circulation offluids into the formations or down one flow conductor and up the otherflow conductor and also be tested in the same manner as the cross-overdevice 60 and a safety valve may be installed in the top landing nipple76b of the nipple assembly 62b in the same manner as in the wellapparatus 20.

It will also be apparent that since the nipple assembly 61b does nothave a bottom nipple, such as the nipple whose internal flange preventsdownward movement of well tools therethrough, two or more landingnipples such as the nipples 251 and 252 may be connected in the firstflow conductor and well tools may be installed and removed therefromeither by wire line tools and methods or pump down tools.

Referring now particularly to FIGURE 7 of the drawings, if it is foundby such testing that the cross-over device has been damaged and may bepermitting flow of fluid through its cross-over passage Pb between thetwo flow conductors, the cross-over passage may be closed by installinga well tool assembly 260 in the top nipple of one of the nippleassemblies 61b or 62b, for example, in the top nipple 70b of the nippleassembly 61b. The tool assembly 260 includes a lock mandrel 261 similarto the lock mandrel 132 having a stop shoulder 262 which engages thestop shoulder 14Gb of the top landing nipple 70b to limit downwardmovement of the tool assembly through the top landing nipple and whoseseal assembly 263 is spaced above its stop shoulder so that it sealinglyengages the seal surface 14% of the top landing nipple 70b. The lockdogs 264 of the lock mandrel 261 are movable into expanded positions inthe lock recess 148b and hold the lock mandrel against upward movementin the top nipple. A lower seal assembly 268 on the lock man.-= drelsealingly engages the lower seal surface 141b of the top nipple. As aresult, when the tool assembly 260 is 17 positioned in the top nipple70b, all fluid flow occuring in the first flow conductor past thecross-over device takes place through the lock mandrel and no flow cantake place between the two flow conductors through the crossover passagePb of the cross-over head 63b.

The tool assembly 260 may be installed in the top landing nipple bymeans of wire line tools including a running tool such as the Otis TypeI Running Tool ilillustrated and described on page 3892 of the CompositeCatalogue of Uil Field Equipment and Services, 1966-67 Edition, and ifsubsequent operation of the well apparatus 20b requires the circulationof fluids down one flow conductor, through the cross-over device andthen up the other flow conductor, the tool assembly 260 may be removedfrom the top nipple 61 by usual wire line tools which will include apulling tool such as the pulling tool 203, prior to the establishment ofsuch circulation.

It will also be apparent that such well tool 260 may also be installedin and removed from the top landing nipple of either the nipple assembly61 or the nipple assembly 62 of the cross-over assembly 60 of the wellapparatus 20 if it is necessary to prevent any possible flow through thecross-over passage P of the cross-over device 60, and that, if desired,a well tool such as a safety valve, could be connected, as at 269, tothe lock mandrel.

It will, of course, be apparent that the well apparatus 20b may becemented in place in a well bore and include surface control assembliesconnected to its flow conductors 21b and 22b of the same type as thecorrespending surface control assemblies of the well apparatus 20.

It will be apparent that the well apparatus 20b allows for greaterflexibility of operation thereof than the well apparatus 20 since it mayhave two or more landing nipples, such as the landing nipples 251 and252 connected in the flow conductor in which a lower pressure ismaintained during normal operation of the well since its standing valve253 does not have to be located above the location at which thepassages, such as the passages 120 h and 120ab, communicate with theother flow conductor below its standing valve 156 b such higher pressurebeing necessary to bias the valves 64b and 65b toward their up perclosed positions.

Referring now particularly to FIGURES 12 through 18 of the drawings, thewell apparatus 300 embodying the invention includes the usual wellcasing C which extends through the well and is provided with sets ofperforaiions 301 and 302 at the locations of the spaced pro ducing earthformations A and B penetrated by the well bore through which the fluidsfrom the formations A and B may flow into the casing and be conducted tothe sur face through the flow conductors 303 and 304, respectively. Thewell apparatus includes a lower packer 305 located in the casing betweenthe two sets of perforations which closes the casing and seals betweenthe casing and the second flow conductor 304 which conducts the fluidsfrom the lower producing earth formation B. The first flow conductor 303which conducts the well fluids pro duced by the earth formation A opensto the casing above the lower packer and below a dual packer 306 whichcloses the well casing above the upper set of per forations and sealsbetween the well casing and both conductors. The lower packer may be ofany suitable com-= mercially available type which may be set eithermechanically or hydraulically as is well known to those skilled in theart. The upper packer may be of the type described and illustrated inthe United States Patent to Carter R. Young, No. 3,288,218, issued Nov.29, 1966, which is modified by the connection therein of the crossoverdevice 308 embodying the invention as will be de scribed below. Thecasing above the upper packer is usually filled at least partially witha liquid such as water or mud so that the pressure in the well casingabove the upper packer is normally higher than the pressures in the twoflow conductors,

The well installation includes a casing head 310 secured to the top endof the casing which closes the top end of the casing. The casing headhas suitable apertures through which the upper ends of the two flowconductors extend and sealing means which seal between the casing headand the flow conductors so that fluids may flow into and out of thecasing at the surface only through a flow conduit 3-12 in which areconnected flow control devices, such as a pressure regulator valve 313and a shut off valve 314. The flow conduit may be connected to a sourceof fluid under pressure, such as a pump or a reservoir, and the like sothat the pressure in the casing above the upper packer may be increased,if desired, by introducing gas under pressure into the casing throughthe conduit until the casing pressure reaches a prede termined value.The pressure within the casing may be decreased to any predeterminedvalue by opening the shut off valve and setting the pressure regulatorvalve at a desired pressure so that the gas under pressure in the upperend of the portion may flow from the casing until the casing pressuredrops to the predetermined value.

The first flow conductor has a surface control assembly 315 connected toits upper end by means of which well tools may be moved into the flowconductor or be re= moved therefrom and 'by means of which fluids underpressure may be caused to flow from the flow conductor or be introducedinto the flow conductor. The surface con trol assembly may include abottom valve 316 of large orifice, an elongate tube or manifold 317 anda top valve 318.for closing the upper end of the tube. A flow conduit=319 having suitable flow control devices connected therein, such asa pressure regulator valve 320 and a shut off valve 321 opens to thetube below the top valve, It will be apparent that when the top valve318 is closed and the bottom valve 316 is open, fluids may flow from theflow conductor and through the flow conduit if the shut ofi valve 321 isopen, the regulator valve 320 being set to permit flow of fluids fromthe flow conductor only as long as the pressure in the first flowconduct-or is above a predetermined value. Conversely, fluids underpressure may be introduced into the flow conductor to maintain thepressure therein at a predetermined value by connecting the conduit to asuitable source of fluid under pressure such as a pump and setting thepressure regulator valve to permit flow into the first flow conduc toronly when the pressure therein falls below a pre= determined value. Ifit is desired to move a well tool or well tool assembly into the firstflow conductor while maintaining a predetermined pressure within thefirst flow conductor, the valves 316 and 321 are closed, the top valve318 is opened and such well tool is inserted into the tube through thetop valve. The valve 318 is then closed and the valve 316 is opened topermit downward movement of the well tool or assembly downwardly intothe first flow conductor. If such tools are to be moved downwardly byfluid pressure introduced into the flow conductor above such well tools,fluid under regulated pressure is then introduced into the tube 317above such tool through the flow conduit 319. If such tools are to bemoved downwardly by a wireline, a suitable stufiing box is secured abovethe top valve to seal about the cable and close the top of the manifoldwhile the tool is being moved in the flow conductor and the manifold bymeans of such line,

The second flow conductor has a similar surface control assembly 325connected thereto which includes a lower valve 326, an elongate tube ormanifold 327, a top valve 328, and a flow conduit 329 in which areconnected flow control devices, such as a pressure regulator valve 330and a shut off valve 331.

The first flow conductor 303 may be a usual string of tubing having oneor more landing nipples, such as the landing nipples 336 and 337connected therein to constitute sections thereof, the landing nipplesbeing connected to adjacent sections of the string of tubing by theusual coupling collars 338. The landing nipples may be of the typedescribed in the patent to J. V. Fredd, No. 2,798,559, issued July 9,1957, each having key grooves 340 and a locking groove 341 in which arereceivable the selector keys 342 and locking members or dogs 343 of thelatch means or lock mandrels which are locatable in selected landingnipples and releasably latched thereby by the latch means. The latchmeans L is also of the type described in the patent to J. V. Fredd, No.2,798,559, issued July 9, 1957. The key grooves of each nipple are ofdifferent dimensions or are differently spaced than the key grooves ofthe other nipples connected in the flow conductor and the latch means Lof the different well tools are provided with the selector keys ofdiiferent configurations so that each well tool may be located andlocked in a predetermined landing nipple of the first flow conducor bymeans of the latch means as is fully described in the patent to J. V.Fredd.

The well tools may be of any suitable desired type. In the wellinstallations 300, the well tool 346 located in the bottom landingnipple 336 of the first flow conductor is a standing valve having avalve member or ball 347 biased toward a lower closed position in thebody 348 by a spring 349 wherein it prevents downward flow of fluidsthrough the longitudinal passage 350 of the body. The lock mandrel L hasseal means 351 which seal between the lock mandrel and the landingnipple. It will be apparent that if the pressure in the casing betweenthe packers is sufficiently higher than the pressure within the flowconductor above the standing valve, the ball is moved upwardly and wellfluids may flow upwardly through the standing valve. If the pressure inthe first flow conductor above the standing valve is of such value thatifs force and the force of the spring exerted on the ball are greaterthan the force exerted on the ball by the pressure in the casing betweenthe packers, the ball will be moved to closed position and thus preventsany downward flow of fluids through the flow conductor into the casingbetween the packers.

The well tool 352 positioned in the landing nipple of the first flowconductor 337 is a safety valve, such as the Otis Type F Tubing SafetyValve illustrated and described on Page 3836 of the 1966-67 Edition ofthe Composite Catalogue of Oil Field Eqripment and Services, which has avalve member 353 that moves to a closed posiiion to stop upward flow offluids through the longitudinal passage 354 of the valve body 355 whenthe pressure differential across the safety valve exceeds apredetermined value, as for example, in the event of failure or damageto the surface r well equipment which would otherwise result inunrestricted fluid flow through the first flow conductor.

The second flow conductor similarly has one or more landing nipples,such as the landing nipples 361 and 363 in which are positioned asanding valve 363 and a safety valve 364 which are identical to thestanding valve 346 and the safety valve 352, respectively.

The valves are movable through the flow conductors and installable inpredetermined landing nipples by a running tool of the type whosestructure and mode of operation is described in the patent to J. V.Fredd, No. 2,798,559, and may be released from the nipples and removedfrom the flow conductors by a suitable pulling tool 366, such as theOtis Type R Pulling Tool illustrated and described on Page 3839 of theComposite Catalogue of Oil Field Equipment and Services, 1966-67Edition.

The portion of the well apparatus 300 including the single packer, thevalves, the flow conductors and the landing nipples connected therein,and the surface equipment of the well are well known to those skilled inthe art and, accordingly, will not be described in greater detailherein.

In order to permit for circulation of fluids down one flow conductor toa location above the upper packer and then upwardly through the otherflow conductor, or to permit installation and removal of the flowcontrol devices in the landing nipples by means of a pump down train oftools 370 which may include piston units or locomo ives 371 and 373,other suitable tools such as jars, not shown, and the above describedrunning and pulling tools connected at the bottom end of the train, itis necessary to provide a cross-over means for selectively providing acir-- culation of fluids between the two flow conductors above the toplanding nipples of the flow conductors in order that the fluids in a Howconductor below a train of tools moving downwardly therein be permittedto flow to the surface through the other flow conductor and to permitfluid pumped into one flow conductor to fiow into the of'her flowconductor below the locomotives of the tra n when t' e train is movedupwardly through such other flow conductor. During normal operation ofthe well apparatus, such cross-over means must prevent fluid flowbetween the two flow conductors to prevent commingling of the wellfluids produced from the two different earth formations.

The upper packer 306, as is fully illustrated and described in thepatent to Carter R. Young, No. 3,288,218, includes a head 400 having apair of passages 402 and 403 and a dependent tubular extension 404 whoseupper end is threaded in the lower end of the first passage 402, a longmandrel 405 whose upper end is threaded in the lower passage 403 of thehead and a hold down body 407 have a passage 408 in which the lower endportion 409 of the tubular extension is slidably telescoped, a passage410 through which the long mandrel extends and plungers 412 which aremovable outwardly of the hold down body to engage the well casing andhold the hold down body against upward movement in the well casing. Thepacker also includes a short mandrel 414 whose upper end is threaded inthe passage 408 of the hold down body. The packer also has packerelements 415, an extender 417, a slip carrier 418 with carrier slips 419which are movable outwardly to expanded positions to engage the wellcasing when the expander moves down-= wardly relative thereto, acylinder 420 and a piston 421 mounted in the cylinder, all of which haveapertures through which the short and long mandrels extend. The cylinderand the slip carrier are provided with a latch or holding assembly 422for releasably holding the slip carrier against downward movementrelative to the cylinder and the cylinder has a latch assembly 423 whichpermits downward movement of the short mandrel rela-= tive to thecylinder which prevents its upward movement relative thereto.

The cross-over device 308 includes a cross-over head 430 and a pair ofnipples 431 and 432. The nipple 431 constitutes the upper portion of thetubular dependent extension 404 of the packer head, its upper end beingthreaded in the lower end of the passage 402 of the packer head and itslower end being threaded on the upper end of the lower portion 409 ofthe extension which telescopes into the passage 408 of the hold downbody and is provided with seal means 433 for sealing therebetween. Thefiow conductor 303 includes a portion 303a which extends downwardly fromthe surface and is provided at its lower end with a collet mandrel 435which is telescopical into the top portion of the passage 402 of thepacker head of the packer, an intermediate upper portion 303b whichincludes the passage 402 of the head and its dependent extension 404, alower intermedate portion 303a which includes the passage 408 of thehold down body and the short mandrel 414 and a bottom portion 303b whichis connected to the lower end of the short mandrel and which includesthe landing nipples 336 and 337 and a bottom section 437 in which a seatring 438 is releasably secured by means of shear pins 439.,

The other nipple 432 of the cross-over device is connected in andconstitutes the top section of the long mandrel 405 of the packer, theupper end of the nipple being threaded in the lower end of the passage410 of the packer head and its lower end being threaded in the upper endof the long mandrel of the bottom section 441.

It will now be apparent that the other flow conductor 304 of the Wellapparatus includes a top portion 304a which extends downwardly from thesurface into the well and has a bottom mandrel 442 which is telecopicalinto the enlarged upper portion of the passage 403 .of the packer headand is releasably secured to the head by means of the lugs 443 of thepacker head and the'J-slots 444 of the mandrel, a middle portion 304bwhich includes the packer head passage 403 and the long mandrel 414, anda bottom portion 304:: which is connected to the bottom end of the longmandrel and includes the landing nipples 361 and 362.

Since the structure and mode of operation of the packer are fullydescribed and illustrated in the patent to Carter R. Young, No.3,288,218, only such details of the struc ture and mode of operation ofthe packer willjbe described herein as are necessary for the fullunderstanding of the operation of the well apparatus 300 and of thecross-over device 308 which is connected in the well packer.

The nipples 431 and 432 extend through vertical paral= lel bores 451 and452, respectively, of the cross-over head 430 and have lateral ports 453and 454 which open to the upper passages 455 and 456, respectively, ofth JIOSS-= over head. The cross-over head also has vertical ports 458and 459 which open at their upper ends to "the passages 455 and456,respectively, and at their lower ends to a main passage 460 of thehead. The ports 458 and 459 are closable by valves 462 and 463,respectively. The head 430 has internal annular recesses in its bore 451in which are disposed O-rings 466, 467 and 468, respectively, theO-rings 466 and 467 sealing between the nipple 431 and the head aboveand below the nipple port 453 and the upper head passage 455, and theO-rings 467 and 468 sealing between the nipple and the head above andbelow the main passage 460. The head also has internal annular recessesin its bore 452 in which are disposed O-rings 471, 472 and 473, theO-rings 471 and 472 sealing between the nipple and the head above andbelow the nipple port 454 and the upper head passage 456 and the O-rings472 and 473 sealing between the nipple and the head above and below itsmain passage 460.

The valve 462 has an annular seal 475 held in an external annular recessof the valve by a split retainer ring 476, the seal engaging a seal ring477 soldered or otherwise suitably secured to the head and about theport 458 to close the port when the valve is in its upper closedposition. The valve is biased upwardly toward its'closed position by aspring 478 whose upper portion extends into the downwardly opening bore479 in the lower end of the stern 480 of the valve and whose lowerportion is received in the upwardly opening portion of enlarged diameterof the passage 481 of a spring retainer 482 which extends into thelongitudinal passage 484 of a tubular seal retainer body 485a. Thespring retainer is secured to the seal body by a pin 487 which extendsthrough a suitable aperture in the retainer body and an external recess489 of the spring retainer which provides a downwardly facing shoulder490 engaged by the pin to limit downward movement of the spring retainerin the seal body. The upper end of the spring, of course, engages thesurface of the valve stem defining the upper end of the bore 479 and thebottom end of the spring engages the upwardly facing stop shoulder 494of the spring retainer.

The seal retainer body is threaded in the lower enlarged portion of avertical passage 497 of the head which opens at its upper end to themain passage 460 and has a reduced upper end portion 498 which limitsdownward movement of a seal or O-ring 499. The O-ring seals between thehead and a tubular seal sleeve 501 whose lower portion is telescoped inthe upper enlarged portion of the longitudinal passage of the sealretainer body.

Upward movement of the O-ring and of a seal assembly 502 disposed in theseal sleeve is limited by a ring 503 whose lower end portion istelescoped over the seal sleeve and whose top internal annular flangeextends over the upper ends of the seal sleeve and the seal assembly.Upward movement of the ring is limited by the downwardly facing annularshoulder 504 of the head. Downward movement of the seal assembly in theseal sleeve is limited by the upwardly facing annular shoulder of abottom internal annular flange 505 of the seal sleeve. The seal assembly502 seals between the seal sleeve and the stem of .the valve. A lowerseal assembly 50 8 also seals between the stem and the seal retainerbody. Downward movement of the lower seal assembly is limited by theupwardly facing annular shoulder 509 of the seal retainer body and itsupward movement is limited by the bottom end surface of the seal sleeve.

It will be apparent that the pressure from exteriorly of the head abovethe upper packer 306 is communicated to the valve stem and exerts anupward force over the area of the stem within the line of sealingengagement of the seal assembly 508 with the stem so that the valve 462is biased upwardly not only by the force of its spring 478 but also bythe well casing pressure about the upper packer as Will'be explainedbelow.

The valve 463 which closes the port 459 when its seal 473a is in sealirgengagement wi.h the seat ring 477a of the head and its mounting meanswhich extend into the bore 510 of the head being identical in structurewith the valve 462, the valve 463 and the elements of its mounting meanshave been provided with the same reference numerals to which thesubscript a has been added, as the corresponding elements of the valve462 and its mounting means.

It will be apparent that the valve 463 like the valve 462 is biasedupwardly toward its upper closed position by the fluid pressure in thewell casing above the sealing elements 415 of the packer.

The cross-over assembly or device 308 is held against upward movement onthe mandrels by a flat key 512 which extends through aligned recesses514 and 515 of the nipples located below the cross-over head. Oppositeend portions are disposed in the upwardly opening recesses 5-16 of aplate 517 through whose apertures 518 and 519 extend the nipples. Theplate is held against downward movement relative to the head by the upwardly facirg shoulders 521 and 521a of the seal retainer bodies 485 and485a which are engageable with the bottom surface of the plate about theapertures 522 and 523 of the plate through which extend upwardly theseal retainer bodies. Downward movement of the crossover device on thenipples is limited by the engagement of the downwardly facing shoulders525 and 526 of the head at the lower ends of its bores 451 and 452 withthe upwardly facing annular shoulders 527 and 528 of the nipples 431 and432, respectively, that the landing nipples are held against bothlongitudinal and rotational movement relative to the head in positionswherein their ports 453 and 454 are in proper alignment andcommunication with the passages 455 and 456 of the head.

The nipple 431 is provided with a top lock recess 431, a top sealsurface 532 below the top lock recess and above the port 453, anupwardly facing stop shoulder 533, a bottom lock recess 534 and a bottomseal surface 535 below the port. Similarly, the o'her nipple has a toplock recess 536, a top seal surface 537, a stop shoulder 538, a bottomlock recess 539 and a bottom seal surface 540.

The well apparatus 300 may be installed in the Well casing in the samerranner as the well apparatus illustraed in the patent to Carter R.Young, No. 3,288,218, by first setting the bottom packer 305 in the wellcasing between the two producing formations and then moving the assemblyof the well packer with the portions 3035, 303d and 3030 of the flowconductor 30-3 and the full length of the flow conductor 304 connectedby means of teh top portion 304a of the flow conductor 304 whose lowerend is secured in the passage 403 of the head. This assembly is loweredinto the well until the bottom portion 3040 of the flow conductor 304engages the lower packer and extends therethrough to open to the wellcasing below the lower packer. The upper portions 303a of the flowconductor 303 is then lowered into the well until its lower endtelescopes into the passage 402 of the packer head 400 and is releasablysecured thereto by means of its collet mandrel. The flow controlassemblies 315 and 325 may then be connected to the flow conductors 303and 304, respectively.

If desired, at least some of the fluids in the well cas= ing, such asdrilling mud, above the lower packer 305 may then be circulated out ofthe casing and replaced by other fluids such as Weighted mud havingdifferent characteristics, e.g., specific gravity, than the drillingmud, T

by pumping such fluids into the flow conductor 303 at the surface whilepermitting flow from the well casing through the flow conduit 312.

The valve 462 of the cross-over device will not open during suchoperation since the pressure in the passage 456 will be substantiallyequal to the pressure in the well casing and, therefore, before the stemof the valve 462 and the spring 478a exerts a sufficient force on thevalve to maintain it in closed position even through the fluid pressureis exerted over a longer upwardly facing area in the port 459 than overthe downwardly facing area of the stem in the body 485a.

When it is desired to set the upper packer 306, a ball 570 is droppedinto the flow conductor 303 at the surface by means of the surfacecontrol assembly 315 in the usual manner by first closing the valves 316and 321 and opening the valve 318 to permit the ball to 'be dropped intothe manifold 317 and then closing the valve 318 and opening the valve316. The ball then drops by gravity through the first flow conductor 303or may be pumped downwardly therethrough by connecting the flow con-=duit 319 to a source of fluid under pressure and opening the shut offvalve 321. When the ball seats upon the seal ring 438 as illustrated inFIGURE 13-8 it closes the bottom end of the flow conductor 303. Thepressure in the flow conductor 303 is then increased as by connectingthe flow conduit 319 to a source of fluid under pressure and setting thepressure regulator valve 320 to insure that the pressure in the flowconductor will be raised to a value sufficiently high to cause settingof the packer but not so high as to cause the shear pin 439 to shear.Such fluid pressure is then communicated through the ports 572 ofthe-short mandrel to a chamber 573 provided by the cylinder 420 and theforce of this pressure exerted on the piston 421 moves the short mandreland the hold down body 407 downwardly relative to the long mandrel 405,the packer elements 415, the expander 417, the slip carrier 418 and theslips 419 until the teeth of the slips engage the well casing C andarrest further downward movement of the expander. Further downwardmovement of the hold down body and the short mandrel relative to the nowstationary expander 417 causes the resilient packer elements to becompressed and expanded into sealing engagement with the well casing.

As the pressure in the short mandrel is increased the valve 462 may bemoved to its lower open position but the cross-over passage P of thecross-over device will remain closed since the valve 463 will remain inits closed position since the pressure in the main passage 460 of thecross-over head exerts a net upward force on the valve, the area of thevalve within the line of sealing engagement of its O-ring 475a with theseal ring 477a being greater than the area of the stem 488a within theline of sealing engagement of the packing assembly 502a with the stem.

When the packer elements are in their expanded sealing position, thepressure in the well casing below the ward movement therein. The fluidpressure in the flow conductor is then increased until the shear pin 439fails and the seat ring and the ball are forced out of the bottom end ofthe bottom section 437 of the flow conductor 303 thus opening the lowerend of the flow conductor to the well casing between the two packers.The lock assembly 423 now prevents upward movement of the cylinderrelative to the short mandrel and the latch assembly 422 preventsdownward movement of the slip carrier,

Well tools may now be installed by means of usual wireline tools and asuitable running tool to which the lock mandrels L may be secured andwhich hold their dogs in their retracted positions until such lockmandrel enters into its preselected landing nipple having selector keyrecesses 340 of the same configuration and dimensions as its selectorkeys 342 whereupon the downward movement of sdch latch mandrel isarrested and the dogs are then moved into their expanded positions inthe lock recess 341.0f the such nipple by downward jars imparted torunning tool which also release the running tool from the lock mandrel.The tools may also be installed in the landing nipples by the use of apump down train of tools 370 by connecting such running tool to thebottom end of the train of tools, the well tool, of course, beingconnected by its lock mandrel to such running too]. If the well tool isto be installed in a landing nipple of such train of tools is insertedinto the manifold 317 while the valves 321 and 316 are closed and thevalve 318 is open. The valve 318 is then closed, the flow conduits 319and 329 are connected to a suitable source of high pressure and thepressure in both flow conductors is then increased to a valuesufliciently great that both valves 462 and 463 of the cross-over deviceare moved to their open position. The pressure regulator valve 330 ofthe flow conduit 329 is set to permit flow therethrough only as long asthe pressure within the flow conductor 304 exceeds the value necessaryto maintain thevalve 463 in its open position. The valves of thecross-over device are thus in their open positions as the fluid is nowpumped downwardly into the upper end of the flow conductor 303 and thetrain of tools is moved downwardly, the fluid below its bottom pistonunit or locomotive 372 flows into the second flow conductor and thenupwardly through the flow conductor 304 to permit the downward movementof the train of tools in the flow conductor 303.

When the lock mandrel of such well tool moves into its appropriatelanding nipple in which it is to be locked, the downward force exertedby the pump down train of tools causes its dogs to be moved outwardlyinto the lock recess of its landing nipple and the running tool to bereleased from the lock mandrel. The bottom locomotive is spaced adistance sufficiently great above such running tool that when the lockmandrel is positioned in its selected landing nipple, the bottomlocomotive is above the port 453 of the nipple 431. The direction ofcirculation of the fluids is then reversed, the pressure regulator valve320 is set to permit flow therethrough only as long as the pressure inthe first flow conductor 303 exceeds the value thereof necessary to keepthe valves of the cross-over device in their open positions and as fluidis introduced into the top end of the flow conductor 304 through itssurface control assembly 325, the fluid will flow downwardly in the flowconductor 304 through the cross-over device and upwardly below thebottom locomotive of the train of tools to move the train of tools withthe running tool secured thereto upwardly through the flow conductor 303and to the surface.

The standing valves 346 and 363 are thus instaled in the bottom landingnipples of the two flow conductors and will thereafter prevent downwardflow through the flow

